Exclusion of Putative CATSPER2 and STRC Gene Deletion and FOXI1 Gene Mutations in a Unique Cohort with Sensorineural Deafness and Male Infertility from South India

Prelingual genetic deafness and male infertility can appear as isolated findings or as part of a syndrome. Deafness-Infertility Syndrome (DIS) was previously reported to be caused due to a rare contiguous gene deletion of CATSPER2 and STRC genes on chromosome 15q15.3. We tested this contiguous gene deletion in a unique cohort of 15 probands with deafness and male infertility, who were partners in assortative mating from south India. Screening for this alleged contiguous gene deletion did not test positive. Given high parental consanguinity, it is possible that infertility and deafness may not be part of a contiguous gene deletion, but two independent events. As a next option we screened another candidate gene FOXI1 (5q35.1), known to independently influence sperm maturation and also encode transcriptional factor of a deafness gene SLC26A4, to implicate for this DIS phenotype. However none of the probands had any pathogenic mutations in FOXI1 gene. Having excluded (i) DIS contiguous gene deletion and (ii) FOXI1 gene mutations’ role in this phenotype, we conclude that this unique cohort’s genetic etiology can be resolved using high-throughput NGS and CNV assessment. This approach may also identify potential linkage to any novel genes.